Thursday, October 28, 2010

Fear Is Spread by Body Language, Study Says

Stefan Lovgrenfor National Geographic News

November 16, 2004

A menacing body posture can be as threatening as a frightening facial expression, according to new research.

In the past, scientists have said that human emotions are communicated mainly by facial expressions. But a new study suggests that body posture may be as important as the face in communicating emotions such as fear.

The discovery suggests that the immediate response to other people's fear may be more automatic than previously thought.

The study shows that images of fear affect the emotional part of the brain. Since the link between the emotional brain and action is stronger than the link between the visual brain and action, viewing fearful body expressions may automatically prepare the observer to respond to fear.

"When we talk about how humans communicate, we always talk about things like language," said Beatrice de Gelder, the neuroscientist who led the study. "But just like in the animal world, we also communicate through our bodies without our conscious minds being much aware of it."

De Gelder is a professor at both Harvard Medical School in Massachusetts, and Tilburg University in the Netherlands. The study is published in the Proceedings of the National Academy of Sciences this week.

Still Images

To date, most investigations of the perception of emotion have concentrated on brain activity generated by the recognition of still images of facial expressions.

For their study, however, de Gelder and her colleagues used video recordings of 18 actors performing emotional actions like opening a door and finding an armed robber standing in front of them. The actors also had to perform neutral actions like pouring water into a glass or combing their hair.

Since previous studies had all used still images, the scientistsfor the purpose of comparisondecided to use still pictures taken from the video clips. But the images showed the whole body with the face of the actor blocked out.

These images were then shown to study participants inside a magnetic resonance imaging (MRI) machine that measured the brain activity of the person watching the pictures.

The researchers found that viewing happy body postures increased activity only in brain regions that processed visual information. However, viewing fearful body postures activated brain regions that process emotional information, as well as those that govern motor processes.